Problem: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Daniel needs to master at least $111$ songs. Daniel has already mastered $21$ songs. If Daniel can master $10$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Solution: To solve this, let's set up an expression to show how many songs Daniel will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Daniel Needs to have at least $111$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 111$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 111$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 10 + 21 \geq 111$ $ x \cdot 10 \geq 111 - 21 $ $ x \cdot 10 \geq 90 $ $x \geq \dfrac{90}{10} = 9$ Daniel must work for at least 9 months.